polyester Spenco insoles with 4-way stretch fabric help prevent blisters while controlling odor EVA forefoot pad provides cushioning and energy return for people who spend a lot of time on their feet Spencore material a 5/32 inch layer of this material absorbs shock and impact to provide our most intense comfort and cushioning Lightweight polysorb polyurethane foam provides arch and heel support Spencore heel-strike pad provides extra cushioning and shock absorption in the heel